In recent times, the Environmental Protection Agency has instituted rigid requirements for discharging or otherwise disposing of wastes into the environment. Commercial effluents, such as laundry waste water contain a variety of contaminants that can no longer be discharged into public sewers or fed to sewage treatment facilities.
State and local environmental protection agencies have adopted the federal standards, and in many cases, have even surpassed them. Therefore, it has become necessary for local industries to purify their waste water, or risk heavy fines and operating restrictions.
Among the industries most susceptible to the new regulations are the commercial laundries, whose waste effluents are particularly afoul with contaminants such as fats, oils, greases, heavy metals, dirt, particulates, solids, etc. By their very nature, laundry effluents accumulate and concentrate these contaminants, and laundry waste water is particularly monitored and regulated by the environmental authorities.
In the past, commercial, industrial and institutional cleaning establishments removed oils and greases from textiles by applying detergents. The waste water was then discharged to the sewer or treated in extreme cases when necessary.
While this method of laundering textiles and discharging laundry waste water effluents was adequate for those times, it no longer provides a viable cleaning and discharging procedure. The extremely high standards presently imposed on the allowable contaminants in the discharged waste water, cannot usually be met utilizing the aforesaid procedure.
Also, one of the major drawbacks of the prior method of processing the effluent, was that it was essentially a batch process. The process was very slow. The effluent had to remain for an extended period of time within large holding tanks for the FOGs to rise out of solution, before skimming could be performed. Various mechanical and chemical means where utilized to froth or foam the demulsified contaminants contained in the waste water, in order to assist in their rise to the top surface of the tank. More often than not, the foaming and frothing additives, where themselves undesirable contaminants that leached into, and polluted the dischargeable waste water.
In all, the previous procedure was generally costly, and inefficient.
The present invention, while particularly applicable to laundry waste effluent purification, can be applied to most any type of industrial waste water management problem.
The current invention can be used to treat waste effluents in car washes, truck wash facilities, oil dealer establishments, airplane washing operations, garages, as well as commercial, industrial and institutional laundries.
The process of this invention is not heavily dependent upon time and/or gravity to separate the emulsion, as was necessary in the aforementioned prior art procedure. Rather, the invention chemically breaks down the emulsion to release and disperse the FOGs in the water phase. The effluent is acidified to cause splitting of the alkaline emulsion, and dispersion of the FOGs within the water. The acidified effluent is then fed through a coalescer, where the FOGs are adsorbed upon an appropriate surface, e.g. a plate or lipophilic material, such as a PVC or polypropylene media pack. The oil molecules rapidly coalesce and gather upon this surface to form droplets. The oil droplets quickly rise to the top of the effluent stream where they are syphoned off and/or pumped away.
One of the major advantages of the invention is that the treatment method can be performed as a continuous process, thereby eliminating the need for large holding tanks, and time consuming effluent holding and storage procedures. Also, harmful and expensive foaming and frothing agents are not employed in this process.